Power tester



July 15, 1941. BENNETT 2,248,938

POWER TESTER Original Filed June 9, 1936 6 Sheets-Sheet l INV EXT OR.

CZ #005 C: 5671 4 57? A T TORNEY July 15, 1941. c. c. BENNETT 2,248,938

POWER TESTER Original Filed June 9, 1936 6 Sheets-Sheet 2 INVEN TOR.

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POWER TESTER Original Filed June 9, 1936 6 Sheets-Sheet 5 v INVENTOR.ZAZ/QZFC'; EMA/7"? BY .r k

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UNITED- STATES JPATE Original application June a, loss. semi No.

84,278. Divided and NT, OFFICE r i this application May 151937,Sel'ialN0.142,888 a I V 3 Claims. .(Ch ass-2t) My invention relatesto machines for testing automobiles more-particularly for testing thepower delivered at the automobiles driving wheels under variousconditions of speed and resistance of the dy- Jnamometer constant, andimposing a constant load on the engine being tested. v

Another object'ls to provide means totest the actual pull of anautomobile, in the nature ofload, thus indirectly testing the power ofthe adraw-bar test, fora quick check of the automobiles engine, and bymeans of whlch conpower, and to employ for such test means w currentlywith the progress of the test, the enwill not interfere with the othertests to be congine may be suitably adjusted. ducted.

-It is an object of this invention to provide a It is an object toprovide a machine for acdevice whereby the engine may be tested in theoomplishing such tests which may be set up withcar and under conditionssimulating road condiin a garage or like establishment, which will taketions, and by a machine whereby a wor up a minimum of floor space, andwhich will be may conveniently control the conditions at the thoroughlyrugged and reliable in operation over test at the same time and from thesame position extended periods. where he stands to work upon the engine,so that 5 Other objects, and more particularly such. as he mayconveniently accomplish adjustments and pertain to details of theoperation of the .o t. test the effect of such adjustments at variouschine, or the mechanical structure thereof, will speeds; and undervarious operating conditions be better understood as this specificationof speed and load, accomp both the adprogresses. justments or the en ineand the control of the y invention comprises the novel chine asconditions of the test, and observing the india whole, and the severalnovel parts thereof, and cations of the tests and of the condition ofthe their relative combination, all as shown in the engine withoutleaving his position at the engine. accompanying drawings, and as willbe hereafter It is a further object to provide such a madescribed inthis specification and more particuchine which is readily adjustable forcars of va- 5 larly pointed out and claimed in the cl which rious sizes,more particularly cars which vary will be found at the end of the same.in length. r In the accom wt drawings I have shown It is a furtherobject to provide a machine my invention in illustrative forms, as nowpreof this character in which the owner of the car ferred by me. or aworkman occupying the drivers seat may l is a side elevation of thecomplete control the engine in the normal manner and machine, showing/anautomobile placed thereon with the usual controls. as it would becontrolled in operative position. while traveling on the road, and atthe same Figure 2 is a plan view of the machine, with time can vary theconditions of the test to simucertain parts broken away. late varyingservice conditions. ure 3 18 a transverse section on the line It is afurther object to provide in a machine 8-8 of 2, illustrating thecontrol and in.

of this character a power absorption device which di'cator panel.

will function properly under tests of appreciable Figure 4 is atransverse section on the line duration, and at varying speeds, and suchpower 4- of Figure 2, illustrating the memeabsorption device asdisclosed takes th form of ter and associated parts.

an hydraulic absorption device, and to the re- Figure 5 is a sectionthrough a driving pulley, quirements of such tests as those indicatedabove. associated with the dynamometer shaft, taken It is an object toprovide an automatic oomon the line 5-! of Figures 2 and 6, and Figure 6pensator, of particular value in extended tests, is a section throughthe same on the li H whereby the resistance of the dynamometer may ofFigure 5. 1 b kept substantially constant, without appre- Figure 7 is aplan view cogesponding to Figciable attention on the part of anoperator. ure 2. showing a modified form of the invention, Moreparticularly, it is an object to maintain Figure 8 is a section on theline H of Figthe volume or water within or passing through ure 7. thedynamometer automatically ata given value, Figure 9 is a sectional viewillustrating the which may be varied at will, decreasing the pressureresponsive means of the torque indicaamount of water within thedynamometer as the tor: torque tends to increase, or increasing the vFigure 10 is an elevation of the drawbar pull amount therein as thetorque tends to decrease, tester. in operative relationship to the rearaxle thereby maintaining the of an automobile.

Figure 11 is a detail sectional view showing an automatic lock for thecar-supporting rollers. to

assist .in backing the automobile oil the device H at the conclusion ofa test.

In testing an automobile it is convenient to run it upon spaced runways9, elevated somewhat above the floor by means of supports 90. In thisway the various testing devices, controls, etc. may be formed as anintegral part of the machine and kept in general below the level of theautomobile chassis, and running gear, and within the general confines ofthe automobile, for economy of floor space, and the entire machine maybe installed as a unit without special preparation, such as the diggingof a pit. However, it will be understood that the machine might well beinstalled in a pit or otherwise upon the floor of the garage, and tothis extent the employment of an elevated framework and runways is amatter of convenience, and the modifications in design for a pitinstallation would be obvious to a man skilled in this art. Access maybe had to the runway by means of ramps, indicated at 9|.

Adjacent the end of the runway which is to support the driving wheels ofthe car, usually the rear wheels, are supported a pair of rollers I andI, one in each runway, and spaced from these rollers to form with them acradle for the wheel W of the car are rollers Ill and I6. Both rollers Iand I are secured upon a transverse shaft I I so that both rollers turnat the same rate of speed. Preferably the rollers Ill and ID are merelyidlers, and serve to permit the wheel W to roll freely, and in doing soto rotate the rollers I and I. These rollers are of sufficient width toaccommodate an automobile tread of any usual width. The entirearrangement may be supported in a frame 92 which is rigidly secured toand in effect forms a part of the main frame.

Mounted upon the shaft II is an hydraulic absorption dynamometer,generally indicated by the numeral 2. The internal construction of sucha dynamometer (for example, of the Froude type) is well known, and theparticular type employed may be any which is found suitable. In effect arotor (not shown) is secured upon the shaft II to be rotated thereby,and a casing 20 is oscillatably mounted upon the shaft II surroundingthe rotor by hearing members 2|. Fluid, usually water, is supplied tothe interior of the dynamometer by a conduit 22, and after passingthrough the dynamometer is discharged by means of a conduit 23. Theamount of air within the dynamometer, which is one means of controllingthe amount of water therein, may be controlled by means of an air ventline 24, connected to the axial part of the dynamometer. Thus the waterwithin the dynamometer transmits the power from the shaft and rotor tothe stator or casing 20, and in so doing absorbs the power delivered tothe shaft II, and produces a ing to the dynamometer, as is customary insuch devices.

It will be observed that the dynamometer is disposed between the rollersI and I, and be-- neath the rear end of the automobile. The dynamometermay be made sufficiently small that it does not project materially abovethe level of the runways 9, sothat all parts of the running gear of thecar may readily clear it in running upon the runways. An hydraulicabsorption dynamometer will absorb large quantities of power overextended periods, and will still continue to function properly andaccurately. Thus located it requires no space in addition to thatoccupied by the automobile.

Being located beneath the rear end of the car, and the workman workingupon the engine being adjacent the front end of the car, it is difficultfor him directly to coordinate adjustments with the indications oftorque, or to read a revolution counter which must be associated withthe shaft I I. Moreover, it would be extremely difficult for him to varythe water supply to or the discharge 7 from the dynamometer, or theventing of the torque which is impressed upon a torque arm 28' securedto the casing 20. Arrangements are made to control the water supply toand the discharge from the dynamometer, and for controlling the ventingof the air. These will be described later, but it is desired to pointout here that the water discharge valve should be located close to thedynamometer itself, and to that end I provide a control valve 26adjacent the dynamometer casing. Because the dynamometer casing must befree to oscillate with the minimum of external resistance, in responseto the torque transmitted to it through the liquid within, flexibleconnections must be employed in the various lines leadsame, whileworking upon the engine. To the end that the workman may effectadjustments in the dynamometer, observe the indications resulting fromits operation and so control the conditions of the test, provision ismade to group all such controls and indications at one point,conveniently to the workman who is working upon the automobiles engine.This is complicated, however, by the fact that the workman is not alwaysin the same position. Some cars have a short wheel base; others areconsiderably longer. I have provided a platform 93 whereon the workmanmay stand, which is supported along one side of the main frame, andwhich is guided thereon as, for example, by the medium of hangers 94, sothat it may be adjusted lengthwise of the runway 9, to place it adjacentthe engine of any car in position upon the runways and upon the rollersI and I. Carried by this platform is a panel 8 (see Figure 3) whereonare grouped various controls and'indicating instruments. The problem ofgrouping the various controls and instruments is complicated by the factthat this platform must be adjustable lengthwise of the runway.

In its simplest form (see Figure 9) when automatic control of theuniformity of the resistance is not required, I provide for the torqueindicator a plunger 2GI, whereon the end of the torque arm 7 25 bears,the plunger working within a cylinder 21 mounted upon the frame, andcommunicating with a pressure gauge 82, suitably calibrated, on thepanel 8 through a pressure line or conduit 28. A revolution counterwithin the casing 3 drives a shaft 30 parallel to the runway 9 at a ratewhich is a function of the speed of the shaft II, and adjacent theplatform 93 this shaft 30 is divided, through gearing within the casing3 I, to drive two flexible shafts 32 and 33, connected respectively to atachometer. 34 and a speedometer 35 on the panel 8. Thus through thetorque indicator 82 and the tachometer 34 the power delivered may becalculated, reference being had to a conversion table, if necessary, forwheels of different diameter, and by the speedometer 35 the workman mayobserve the speed at which the car would be operating were it upon theroad. The tachometer may, of course, be calibrated in terms ofrevolutions of the engine instead of revolutions of the wheel W, if thatbe preferred, although this is main or other suitable source, pretersblyunder pressure. past the valve 4! on the panel, thence past the valve 6and thence into the interior of the dynamometer 2," through the pipe 2.The water pressure is indlceted by s gauge 88, connecied by s suitsbleconduit to the water supply line. The water discharge line 23 leads to adrain or to any suitable receiver, but since the discharge control valveE6 is located closely adjacent the dynsmometer I provide means tocontrol this valve from the platform 93. Thus the stem or the valve 28is extended, as lndicatw st 85, and is connected through-bevel gesrs orlike devices st le to s shsit tl extending lengthwise oi one of therunways 9 to s point sdiscent the platform es where it is connectedthrough s flexible shalt duor like means to control hsndle so on thepanel s. 3y these or any eduivslent means the disclisrge of water fromthe dynamometer may to controlled without leaving the platform.Similarly the sir vent pipe 24% leads lengthwise or the runways ii, endcommunicates through siiesihle hose st to s control valve so upon thepanel It is sometimes desirable as s uuicls check on the power of onautomobile to determine what force is developed, us in pulling. Such ctest will indicate to s. prospective customer whether or not his engineis developing the power it should. An automobile, being driven lay oninternal coinbustlon engine, cannot be coupled while ststlon cry to a.drswbsr end then echieve any pull, but the automobile can he run on thismachine at any desired speed, without appreciable resistance, and thenresistance can he thrown in. by admitting water to the dynemometer,tending to stop the rollers i end i so that in efiect the sutomobiletends to roll forward, and the amount of pull developed in so doing maybe measured. 7

To this end I provide the mechanism host shown in Figure 10. A braceframe 92 is tilteble about a transverse pivot it, and likewise isswingsble about it longitudinal unis, so that it may swing from theposition shown in Figure 10, which is the operative position. to astored position, as shown in Figure 2, where it is out of the wsy. whenin the operative position its end opposite the pivot it bears upon a.plunger l8, slmi lsr to the plunger tel and. connected by s pressureline It to damage upon the panel e. Since ditlons. 'lheloodmybevsriedbyoperetlonot the dynemometer control; and the speed byoperctlon of the normal engine controls. He is also automoblle's engine,.snd the cylinder pressure gauge so likewise hes a ilemhle connection 52which can be connected through the spark plug hole into any oi thecylinders of the engine. He

' is interested-in the Pressure of the fuel pump which must be keptrather closely within low limits, and in the heck pressure in theexhaust line, sud a sensitive low prmsure gouge so is provided with stuhe B8 or connection to either.

Sllfih $013198, UK it)? so; .021 pug-pages v In order to determine thegcsollne consumption of the engine in s given length of time I- rnsymount noon-the usnel s s flow meter consisting of o grsdueted containerus which may cooling efiect oi movement through the air, and

he connected through c flexible conduit so with the fuel, feed meters ofthe supply connection therewbelns disconnected for the purpose oi thetest, and the workmen may observe the gasoline consumption of the car atany speed or under eny conditions of load, since these may m veriedeither by varying the dynamometer controls or by governing the enginewith its normal controls while he is working upon it, or both.

The exhaust gases of the motor while under test are prefershly led tothe outside air means of conduit ss hsving u flexible connection 53which may be connected directly to the end of the engine's exhaust pipe,as is indicated in Figure 1. This svoids contamination of the air,

or danger from. carbon monoxide, in s closed h garage.

An engine, while undergoing such a. test, may heat up considerably,since it is not subject to the its fun is not so designed as to keep itcool for long periods while standing still. To cool the engine, andthereby to obtsin conditions more nearly approximating road conditions,I prefer to employ a. blower s, which may be driven from the the gauget2 slso measures pressure, this gouge may be provided with a second setof celihro= tions, and valve 85 may be movable into two slternstivepositions, either to connect the pressure line it with the sense, or toconnect the pressure line it therewith. in the first position, as mownin Figure 3, it will measure the drawber pull. the upper end of theframe Wheing connected by a chain it or like means to the side oi thecar, end-in the second position it will register the torque developed atthe wheel W as.

a function of the pressure developed by the plunger 25!. when the frame12 is not in use theengine, and can control and vary those conshaft ll.or independently; and which discharges through a conduit so, the end Mof which is curved back and directed into the radiator or over theengine of the automobile. Preferably the outer section so of thedischarge conduit 66 is telescopically mounted upon theinnersection,ssisbestv seenin Figure 7, so the-tit is adjustable for cars oi difierentlengths, to the end that the discharge end'ti may be placed closelyadjacent the front or the rsdiator, as is seen in Figure 1, whatevermsy'be the length of the car.

Since in, some installations, or tor tests of short duration, it isunnecessary or it msy not be desired to employ the blower or equivalentengine; cooling means, I prefer that it be supported upon separate framemembers 96, secured to the frame members 92 and projecting forwardlythereof, so that it may be omitted ii the user prefers. In the framemembers 90 is Journsled a. shaft 84 carrying the blower blades (notshown) and a, pulley N. by means of which the blower is rotated. In thisform shown in Figures 1 and 2, the pulley OI the regular is driven by abelt 60 from a pulley 1 upon the shaft H. I

The blower must operate at a comparatively high speed to attainreasonable efllciency, and therefore the pulley I is made larger thanthe pulley 65. However, if the speed of the shaft 04 was always indirect ratio to the speed of the shaft II, as the speed of the shaft llincreases the blower would eventually be operating at speedsconsiderably in excess of any efllcient speed. For that reason I preferto provide automatically operable means whereby with increase of speedof the shaft II the relative speed of the blower is reduced, thusoperating the blower at all times between efficient limits of speed.

The arrangement for accomplishing this is shown in Figures 5 and 6. Thepulley I is formed as a reservoir to contain a liquid such as oil.Within it is mounted a gear pump casing 10 forming an integral part ofthe pulley, and having in-- lets H to the pump chamber within. Theprimary gear 12 of the pump is indirectly secured to the shaft II- bymeans of a clutch 61 and rotates therewith. Idler gears 13 are journaledwithin the gear casing 10, and when they are rotated by the primary gear12 they serve to drawoil inward through the ports II and to dischargethis fluid from within the gear pump housing 10 through the single port14, which is controlled by a valve 15. With the pulley rotating in thedirection of the arrow A (Figure 6), at slow speed, the valve 15,mounted on the arm 10, is held closed by a spring 11. As a result theoil cannot be discharged from within the gear pump housing 10; the gears12 and 13 are locked together, and the pulley I turns at the same speedas the shaft H. As the speed of rotation of the pulley 1 increases,however, a weight 18 upon the arm 16 is thrown outwardly by centrifugalforce in opposition to the spring ll, to a greater or less extent,depending upon the speed of rotation, and in consequence the valve 15 isopened more or less, permitting discharge of oil from within the housing10 and permitting the idlers 13 to rotate planet-like about the primarygear 12. In this manner the speed of the pulley 1 relative to the speedof the dynamometer 2 is decreased at higher speeds of the latter, andconsequently the blower 6 is driven at a slower relative speed forhigher speeds of the engine, and is thereby maintained within efficientspeed limits, whatever may be the speed of the engine.

As will now be evident, an automobile is run upon the runways 9 untilthe driving wheels are cradled between the cooperating rollers l and I0,I and i. With all connections made as are required by the particulartest to be performed (for example the exhaust conduit 56 and theconduits and 54), the automobiles engine isdriven under conditionssimulating road or service conditions. The resistance or load may bevaried by varying the rate of discharge'of water from the dynamometerthrough the: valve 26, or by controlling the rate of admission of waterby the valve 4|, or the discharge of air by the control 44. In this wayloads may be imposed on the automobile engine corresponding to hillclimbing and the like, and the engine-may be tested at various speedsunder'various conditions by the workman upon the platform 93, who is atthe same time adjusting and manipulating the engine. The workman mayoccupy the driver's seat of the automobile and control its engine by theusual controls in the car, or the owner of the car may do so, and whilecontrolling the engine ascaeae in this way, the conditions under whichit is operating may be varied and controlled by means of the valve 4,this being placed conveniently to be operated by the occupant of thedriver's seat of the car, and serving to control the water supply to thedynamometer. Such a control might, as is recognized by those familiarwith dynamometers, be connected to the discharge line of thedynamometer. During all this time the engine is being cooled in thenormal manner by the blower 0 without the expenditure of an undue amountof power, and at an eflicient speed of the blower. If desired, the powerabsorbed by the blower 0 may be suitably calculated or measured andindicated upon the panel 8. The blower or its drive pulley I may bedisconnected when extreme accuracy is desirable. To this end I providecomplemental clutch members 61, previously referred to, one keyed to theshaft II and one secured to the gear 12 (see Figure 5), engageable anddisengageable by a yoke 60 controlled by a suitable handle (Figures 1, 2and 4).

In Figures 7 and 8 the blower has been shown as loosely mounted upon theshaft ll, driven by a pulley 19, which may, if desired, be formedsimilarly to the pulley I previously described. being in this instancemounted upon the shaft of an idler roller 10.

In this form I have shown an automatic con trol for the dynamometer,for'use particularly when the car is to be tested over a considerableperiod of time, and its speed should be kept constant during such atest. This may be employed, for example, in running in a new car, or acar which has been overhauled, or in an extended fuel consumption test.

In this form the dynamometer casing is provided with an additionaltorque arm 29, which with increase of torque within the dynamometertends to rise. It is connected to an arm 400 pivoted at I and carryingat its opposite end a reservoir 402 filled with water. Flexible conduits403 and 404 afford a circulating connection between the dynamometer andthe reservoir 402, and are controlled by suitable valves 405 and 406. Acounterweight 401 may be employed to counteract the tendency of thewater-filled reservoir 402 to oscillate the dynamometer.

Now as torque within the dynamometer increases, it tends to raise thetorque arm 29, thereby tending to lower the reservoir 402. Since thereservoir 402 is substantially level with the dynamometer casing 2,lowering the reservoir tends to lower the level of water within thedynamometer. It is well known that as the water level within anhydraulic absorption dynamometer is lowered the power absorption thereofdecreases, and consequently the tendency to raise the torque arm 29 islessened, and this is brought back to its initial position by thecounterweight 401, thus again raising the water level in the reservoirwith respect to the water level within the dynamometer, and againincreasing the torque in the dynamometer. Actually there is noappreciable oscillation or tendency to rise and fall, but equilibrium issoon reached, and the dynamometer continues to rotate undersubstantially the same load, although if the load varies because ofvariation' in the operating conditions of the engine, this arrangementwill automatically compensate for such changed conditions, and willmaintain the engine running at a substantially constant speed and load.While not shown herein, suitable arrangements may be made for coolingthe water as it circulates in this system, and similarly with respect tothe pulley I arrangements may be made for cooling the fluid circulatingtherein, but as such arrangements are common and form no essential partof this invention they have not been shown.

In order that a car may be backed off the machine, whenever desired,without an attendant locking the rollers l and I0 (and unless these arelocked to resist reverse movement of the wheels the car cannot be backedoff by its own power), I may provide a lock which is disengaged byforward driving rotation of wheel W and rollers l0 and HI, but whichautomatically locks to prevent reverse rotation. Any suitable means tothis end may be employed, that shown in Figure 11 being typical. An armi1, pivoted upon the frame at one end, has two shoes l8 and I 8', atleast one of which is adjustable for wear, engaging outside and insidethe rim of a roller ID or ID, as the case may be. A stop pin 19 limitsswinging of the arm i1 upward, because of frictional engagement of theshoes with the roller when driven in a forward direction, to a positionwherein there is no appreciable binding efiect on the roller. If thewheel W tends to drive the roller [0 reversely, the shoes bind on theroller and lock it effectively against move ment, so that, the rollerbeing stationary, the wheel W may readily back the car off.

The invention theretofore described is disclosed in my copendingapplication Serial No. 84,273, filed June 9, 1936, this applicationconstituting a division thereof.

I desire to point out that while an hydraulic absorption dynamometer hasbeen found most suitable for the purposesof this machine, it is notoutside the scope of my invention to substitute therefor otherequivalent power absorption .devices as are common in the art, and whilecertain-thereof, as for example a Prony brake, will not operatesatisfactorily for long continued tests, it may be found entirelysatisfactory for short test. Various other changes may be made in thecharacter, arrangement, and control of the device, without departingfrom the spirit and scope of myjnvention, and I do not desire to berestricted as to such matters other than as is required by the appendedclaims.

I claim:

1. A machine for testing automobiles comprisblower and rollers, adischarge conduit leading from the blower, its discharge end beingdirected rearwardly toward the radiator of an automobile received on therunways, and means to adjust the position of such discharge end to placeit immediately in front of automobiles of varying,

lengths.

2. In a machine for testing automobiles com- "prising a dynamometer andmeans to deliver power thereto from an engine at a speed related indirect ratio to the speed of such engine, a blower having a dischargeoutlet directed to cool such engine, means to drive said blower fromsuch engine including a driving shaft and a pulley thereon internallychambered to form a liquid reservoir, a gear pump and casing thereforenclosed therein and having inlet ports freely open to the reservoir,and a discharge port opening into the reservoir, the primary gear ofsaid pump being secured on said shaft, valve means to close saiddischarge port, yieldable means normally holding said valve meansclosed, and means responsive to centrifugal force and carried by thepulley to open said valve means in response to increased speed of thepulley thereby to lessen automatically the driving connection betweenthe shaft and pulley and to decrease the ratio of the speed of theblower to the speed of the dynamometer.

-3. A machine for testing automobile engines comprising a shaft adaptedto be driven from such engine, an hydraulic absorption dynamometercasing oscillatable upon said shaft, 9. dynamometer rotor within thecasing and secured to ing a pair of runways spaced apart to receive theshaft, a reservoir connected to the casing for circulation of liquidtherethrough, means supporting the reservoir for vertical movement froma normal position substantially level with the dynamometer casing, andmeans operable in response to oscillation of said casing under increasedtorque to lower the reservoir, and thereby the level of liquid in thecasing to lessen the torque automatically, and vice versa.

CLAUDE C. BENNETT.

